The heavy brass contact blocks are bounds to the vulcanite
plate by the souble nut system. The plugs and luga are cut
to a fine taper and are interchangeable. The plug heads are
machine moulded of bakelite. Each resistor independentyly
mounted with double leads. Accuracy of constantan coils. 1%
for lower values and 05% for the higher valued fitted in polished
wooden box.